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Abstract- Micro and nano-fluidic mixing nowadays is a very important area in research due to its crucial role in new technologies and applications such as biomedical and biochemical synthesis. Due to the low velocities associated with microscale flow, it is often very difficult to mix fluids in a rapid and homogeneous manner. One of the methods of enhancing fluid mixing is to obstruct the fluid flow using vanes or panels known as baffles. In this paper, a Computational Fluid Dynamics (CFD) approach is used to study the effect of baffles on the mixing performance in a passive micromixer. The numerical method is verified by comparing its obtained results with experiments and numerical results published earlier. Rectangular, semi-circular and triangular baffles have been considered for investigating the effects of baffle geometry on mixing performance. Furthermore, the effects of channel inlet angle and baffles offset in mixing performance are studied. As the results show, there is a two-fold increase in mixing performance in the baffled cases as opposed to the simple case.
Keywords- Computational fluid dynamics, passive micromixer, baffle, mixing index, FEM
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1. INTRODUCTION
Microfluidics is a synergy of science and engineering applied to fluid mechanics, involving characteristic dimensions in the micron scale. Examples of application areas include chemical analysis, biological interfacing, medical diagnostics, energy conversion and toxin detection. Characteristic dimensions such as channel widths or orifice diameters are typically on the order of 10 to 100pm. In lab on chip or Micro Total Analysis Systems (pTAS), it is often necessary to mix reactants. For example in biology, in order to identify proteins in an unknown sample, proteins are fragmented by mixing them with enzymes. Proteins can then be characterized using mass spectrometry analysis of the resulting fragments.
Rapid and effective mixing is the basic requirement for a successful biochemical analysis. To reduce the analysis time, rapid mixing and improved procedure control can be carried out in «TAS [1],
Microfluidic micromixers can be categorized into two major groups: Active and Passive micromixers. In active micromixers external energy is given to system in order to accelerate the mixing performance. This external energy can be acoustic [2, 3], magnetic [4, 5], electrokinetic [6, 7], mechanical [8] or thermal [9], Generally, active micromixers have...